Caught between saving data and doing this on view, leaning toward on view

web/modules/custom/geo_citation/geo_citation.module

@@ -1,3 +1,33 @@
 <?php
 
+/**
+ * Implements hook_ENTITY_TYPE_update() for Drutopia article content.
+ */
+function geo_citation_article_update(Drupal\Core\Entity\EntityInterface $entity)
+{
+  $article_type = $entity->field_article_type->getValue();
+  // If it's not a GEO Original article, there's nothing for us to do.
+  if (!$article_type == 6) {
+    return;
+  }
+}
 
+/**
+ * Implements hook_entity_extra_field_info().
+ */
+function geo_citation_entity_extra_field_info() {
+  $extra = [];
+  $extra['node']['article']['display']['geo_citation'] = [
+    'label' => t('GEO Citation'),
+    'description' => t('Re-presents title, author, date and other information in a standard citeable format.'),
+    'weight' => 90,
+  ];
+  return $extra;
+}
+
+/**
+ * Implements hook_ENTITY_TYPE_view() for Drutopia articles.
+ */
+function geo_citation_article_view(array &$build, \Drupal\Core\Entity\EntityInterface $entity, \Drupal\Core\Entity\Display\EntityViewDisplayInterface $display, $view_mode) {
+
+}